> An intruder using administrative permissions acquired through an on-premises compromise to gain access to an organization’s trusted SAML token- signing certificate. This enables them to forge SAML tokens that impersonate any of the organization’s existing users and accounts, including highly privileged accounts.
https://blogs.microsoft.com/on-the-issues/2020/12/13/custome...
> An intruder using administrative permissions acquired through an on-premises compromise to gain access to an organization’s trusted SAML token- signing certificate. This enables them to forge SAML tokens that impersonate any of the organization’s existing users and accounts, including highly privileged accounts.